lankapay_justpay_flutter 0.2.4

Flutter plugin bridging LankaPay LPTrusted (JustPay): getDeviceId and createIdentityAndSign over MethodChannel justpay_sdk/methods. Host apps must supply bank JSON and SDK binaries per README.

Complete setup guide: lankapay_justpay_flutter

This document is the full, ordered checklist for integrating the plugin. Follow it top to bottom the first time you integrate. Example XML in the Android and iOS sections matches common MID patterns for MNV cleartext hosts; always confirm values against your official MID.

Related files in this repo

Item	Location
Short overview	README.md
Example app	example/
Method channel name	justpay_sdk/methods

---

Table of contents

1. Before you write any code
2. Update your Flutter project
3. Add the Dart dependency
4. Android — LPTrusted AAR
5. Android — Gradle (app module)
6. Android — Config JSON in res/raw
7. Android — Permissions (AndroidManifest.xml)
8. Android — Network security (cleartext / MNV)
9. Android — ProGuard / R8 (release)
10. iOS — LPTrusted xcframework layout
11. iOS — CocoaPods
12. iOS — Bundle JSON
13. iOS — App Transport Security (ATS)
14. iOS — Xcode build settings
15. iOS — Embed & Sign the framework
16. Dart — Usage in your app
17. Config JSON — Required keys (reference)
18. Verify the integration
19. Migrating from embedded native JustPay code
20. Troubleshooting

---

1. Before you write any code

Obtain from your bank / LankaPay onboarding (not from this open-source repo):

Asset	Android	iOS
justpay.json	Place in res/raw	Add to Runner bundle
mnv.json	Place in res/raw	Add to Runner bundle
Native SDK	LPTrustedSDK.aar	LPTrustedSDK.xcframework

---

2. Update your Flutter project

1. Use a stable Flutter channel and a Dart SDK compatible with the plugin’s pubspec.yaml (environment.sdk).

2. From your app root:

   flutter upgrade
   flutter doctor -v
   

Fix any Android SDK / Xcode / CocoaPods issues flutter doctor reports before continuing.

---

3. Add the Dart dependency

In your app’s pubspec.yaml:

dependencies:
  flutter:
    sdk: flutter
  lankapay_justpay_flutter: ^0.2.4   # or path: / git: for your team

Then:

flutter pub get

Import:

import 'package:lankapay_justpay_flutter/lankapay_justpay_flutter.dart';

---

4. Android — LPTrusted AAR

1. Create the folder android/app/libs/ if it does not exist.

2. Copy the bank’s file LPTrustedSDK.aar into:

   android/app/libs/LPTrustedSDK.aar

   Use exactly this filename unless you change every Gradle reference yourself.

3. The plugin’s Android module uses compileOnly against:

   $rootProjectDir/app/libs/LPTrustedSDK.aar

   (same path relative to your Flutter app’s android/ folder). If this file is missing, Android Gradle fails with an explicit error from the plugin — that is expected until the AAR is present.

---

5. Android — Gradle (app module)

Edit android/app/build.gradle or android/app/build.gradle.kts.

Kotlin DSL (build.gradle.kts) — recommended pattern

Add a dependencies { } block (or merge into your existing one):

dependencies {
    // Required: packages LPTrusted into the APK. The plugin only compileOnly-compiles against it.
    implementation(files("libs/LPTrustedSDK.aar"))

    // MID-aligned versions (OkHttp 4.9.3, json-simple non-transitive).
    // The plugin also declares OkHttp + json-simple; duplicating here is optional but explicit.
    implementation("com.squareup.okhttp3:okhttp:4.9.3")
    implementation("com.googlecode.json-simple:json-simple:1.1.1") {
        isTransitive = false
    }
}

Groovy (build.gradle)

dependencies {
    implementation files('libs/LPTrustedSDK.aar')
    implementation 'com.squareup.okhttp3:okhttp:4.9.3'
    implementation('com.googlecode.json-simple:json-simple:1.1.1') {
        transitive = false
    }
}

applicationId / flavors: The value of package inside justpay.json must match the built app’s applicationId (including flavor suffixes such as .dev). If they differ, identity and signing will fail.

---

6. Android — Config JSON in res/raw

1. Copy your bank’s files to:

   • android/app/src/main/res/raw/justpay.json
   • android/app/src/main/res/raw/mnv.json

2. Resource names are the filenames without extension: justpay and mnv. Do not rename to justpay_config.json unless you also change native loading logic (this plugin expects those two names).

3. The plugin validates required keys before calling the SDK (see section 17).

---

7. Android — Permissions (AndroidManifest.xml)

JustPay / LPTrusted needs network access. Declaring network state is optional but useful for connectivity-aware behavior.

Minimum recommended for JustPay networking

Inside <manifest> (not inside <application>):

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Other permissions

Typical banking apps also declare permissions for notifications, camera, biometric, and so on. Those are not required by this plugin unless your app uses those features. For JustPay-only networking, INTERNET (+ optionally ACCESS_NETWORK_STATE) is the core set.

Optional (only if your MID or bank doc says so): Some integrations mention telephony. Follow your MID if it requires READ_PHONE_STATE or similar.

Application attribute for network security

On <application>, point to your XML config (see next section). Example:

<application
    android:name="${applicationName}"
    android:label="your_app_name"
    android:icon="@mipmap/ic_launcher"
    android:networkSecurityConfig="@xml/network_security_config">
    <!-- activities, meta-data, etc. -->
</application>

---

8. Android — Network security (cleartext / MNV)

Mobile network validation (MNV) often uses HTTP to specific operator endpoints. Android 9+ blocks cleartext unless you allow it per domain.

1. Create android/app/src/main/res/xml/network_security_config.xml.

2. Example content (replace domains with those from your MID if they differ):

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">mobileauth.ideabiz.lk</domain>
        <domain includeSubdomains="true">gsmacnv.mobitel.lk</domain>
        <domain includeSubdomains="true">apihub.hutch.lk</domain>
        <domain includeSubdomains="true">heapihub.hutch.lk</domain>
    </domain-config>
</network-security-config>

3. Ensure AndroidManifest.xml references it (see section 7).

Important: If your bank’s MID lists different hosts for sandbox/production, replace these domains accordingly. The block above is an example, not a substitute for your MID.

---

9. Android — ProGuard / R8 (release)

1. This plugin publishes consumer-rules.pro with:

   -keep class com.lankapay.justpay.** { *; }
   

2. If LankaPay or your bank supplies additional ProGuard rules, merge them into your app’s proguard-rules.pro (or the rules file your release build uses).

3. Always run a release build on a real device and exercise JustPay onboarding before store submission.

---

10. iOS — LPTrusted xcframework layout

1. Under your Flutter app’s ios/ folder, use this layout (matches this plugin’s podspec FRAMEWORK_SEARCH_PATHS):

   ios/
     JustPaySDK/
       LPTrustedSDK.xcframework   ← entire xcframework bundle here
     Podfile
     Runner/
     ...
   

2. Copy the bank’s LPTrustedSDK.xcframework into ios/JustPaySDK/ so the path is:

   ios/JustPaySDK/LPTrustedSDK.xcframework

---

11. iOS — CocoaPods

1. Open a terminal at your_app/ios/.

2. Run:

   pod install
   

3. If you change the plugin version or iOS native deps, run again:

   pod install --repo-update
   

4. Open Runner.xcworkspace in Xcode (not Runner.xcodeproj alone).

Podfile platform: Use at least iOS 13.0 (MID). Your team may standardize on a higher minimum; that is fine as long as it meets MID requirements.

---

12. iOS — Bundle JSON

1. In Xcode, select justpay.json and mnv.json.
2. In the File inspector, under Target Membership, enable Runner.
3. Confirm both appear under Build Phases → Copy Bundle Resources.

Filenames on disk should be justpay.json and mnv.json so Bundle.main.url(forResource:withExtension:) finds them.

---

13. iOS — App Transport Security (ATS)

iOS blocks insecure HTTP unless you declare exceptions. Add NSAppTransportSecurity for the same operator hosts you allow in Android cleartext (example below; align with your MID):

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>mobileauth.ideabiz.lk</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
        <key>gsmacnv.mobitel.lk</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
        <key>apihub.hutch.lk</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
        <key>heapihub.hutch.lk</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
        </dict>
    </dict>
</dict>

How to add in Xcode: Open Runner → Info.plist as source code, or use Information Property List editor: add App Transport Security Settings → Exception Domains and mirror the keys above.

Again: confirm hosts with your MID for non-production environments.

---

14. iOS — Xcode build settings

Per MID:

Setting	Value
iOS Deployment Target	≥ 13.0 (MID minimum; your app may use a higher floor)
Enable Bitcode	No (MID)

In Xcode: Runner target → Build Settings → search “Bitcode” → Enable Bitcode → No.

---

15. iOS — Embed & Sign the framework

1. In Xcode, select the Runner target → General → Frameworks, Libraries, and Embedded Content (or Build Phases → Embed Frameworks).
2. Add LPTrustedSDK.xcframework.
3. Set embed option to Embed & Sign if that is what your MID / bank instructions require.

The plugin podspec adds search paths and -framework LPTrustedSDK for the plugin target. If you still see link errors, confirm the xcframework path, run pod install, and compare Frameworks, Libraries, and Embedded Content with a working native sample from your bank or MID package if one was provided.

---

16. Dart — Usage in your app

final justPay = LankapayJustpayFlutter();

// 1) Optional: device id for your backend
final deviceId = await justPay.getDeviceId();

// 2) challenge from your bank API; contentToSign = e.g. terms text user agreed to
final result = await justPay.createIdentityAndSign(
  challenge: challengeFromApi,
  contentToSign: termsPlainText,
);

if (result.success) {
  final signature = result.signature;
  final mobileReference = result.mobileReference;
  // Send signature + mobileReference to your bank API per integration guide.
} else {
  // Show result.message to the user or log for support.
}

Threading: Native callbacks complete on the platform main thread; the plugin returns a Future to Dart as usual.

---

17. Config JSON — Required keys (reference)

These are validated before the SDK runs (mirroring typical native LPTrusted integration checks).

justpay.json (string values, non-empty after trim)

Key
url
package
justpay_code
key_encipher
key_signer
justpay_cert
issuer

mnv.json

Key
dialog
hutch
mobitel

If any are missing, you get a structured error message in the Dart result (Android) or the same shape from iOS.

---

18. Verify the integration

Use this checklist on a physical device when possible (MNV often depends on real carrier data).

• ❌ flutter pub get succeeds.
• ❌ cd ios && pod install succeeds.
• ❌ Android: LPTrustedSDK.aar exists at android/app/libs/LPTrustedSDK.aar.
• ❌ Android: justpay.json / mnv.json exist under res/raw/ with correct names.
• ❌ Android: network_security_config.xml present and referenced in the manifest.
• ❌ iOS: LPTrustedSDK.xcframework under ios/JustPaySDK/ and embedded per MID.
• ❌ iOS: JSON files in Copy Bundle Resources.
• ❌ iOS: ATS exceptions for the four domains (or MID-approved set).
• ❌ justpay.json package matches Android applicationId.
• ❌ getDeviceId returns a non-empty string when the SDK is correctly linked (empty often means iOS framework not linked or stub path).
• ❌ createIdentityAndSign completes with success: true in a full test onboarding (uses bank sandbox as directed).

---

19. Migrating from embedded native JustPay code

If you previously registered a custom MethodChannel in MainActivity / FlutterActivity or AppDelegate that called LPTrusted directly:

1. Add lankapay_justpay_flutter to pubspec.yaml.
2. Remove your custom JustPay MethodChannel setup and any duplicate LPTrusted handler classes from the host app (the plugin registers justpay_sdk/methods on its own).
3. Replace your Dart bridge class with LankapayJustpayFlutter from this package.
4. Keep Firebase, notifications, other channels, and unrelated manifest keys as they are.
5. Run full JustPay regression on Android and iOS.

---

20. Troubleshooting

Symptom	What to check
Gradle: AAR not found	Path android/app/libs/LPTrustedSDK.aar and spelling of filename.
Android: “Missing res/raw/…”	Files named justpay.json / mnv.json under app/src/main/res/raw/.
Android: cleartext / SSL errors	network_security_config.xml domains vs MID; manifest networkSecurityConfig.
Android: package mismatch	justpay.json package vs applicationId (flavors).
iOS: import LPTrustedSDK / link errors	ios/JustPaySDK/LPTrustedSDK.xcframework, pod install, Embed & Sign.
iOS: HTTP load fails	ATS entries in Info.plist for operator hosts.
iOS: empty getDeviceId	Framework not linked (stub path) or SDK not initialized; recheck Embed & Sign, JustPaySDK path, and pod install.
Dart: success: false with config message	JSON keys missing/wrong; read message string.
Debug logs (recommended)	Android: view logcat and filter by tag LankapayJustpay. iOS: view the Xcode console for lines starting with [LankapayJustpay]. Dart: debug console output (only in debug mode).
Debug mocks (optional)	In debug builds you can enable failure simulation as success. This can help you continue UI/backend registration flow without native success. Enable with LankapayJustpayFlutter(enableDebugMocks: true). Backend may still reject dummy signature or mobileReference if it validates strictly.
Release-only crashes	R8/ProGuard rules; test release on device.

---

Quick command recap

# From app root
flutter pub get
cd ios && pod install && cd ..

# Android
cd android && ./gradlew :app:assembleDebug && cd ..

# iOS (from app root)
flutter build ios --no-codesign

If anything in this guide conflicts with your bank’s MID, the MID wins.